The present invention relates to side wall components for reusable, industrial shipping and storage containers. In particular, the invention relates to side wall components for use with collapsible shipping and storage containers.
Various reusable shipping and storage containers are known in the art that are adaptable for general industrial and agricultural uses, including storage and transport of manufacturing tools and parts, packaged goods, and bulk commodities. Such containers range in size from large capacity cargo containers to smaller and lighter-weight containers designed for such commodities as bakery goods and farm produce.
Among these different commercial container designs, collapsible containers that have foldable side walls and end walls for compact storage and transport of the containers when emptied are well known in the art. A number of these containers are designed with pallet-type bases and upright container walls that are pivoted to the base. The walls and base are adapted to permit the walls to be pivotally erected on the base to a locked, upright position during use, and later collapsed into a folded position against the upper surface of the base for return transport or storage.
Exemplary among the foregoing types of containers are the container designs set forth in U.S. Pat. No. 4,674,647, issued Jun. 23, 1987 to Gyenge et al., U.S. Pat. No. 4,775,068, issued Oct. 4, 1988 to Reiland et al., U.S. Pat. No. 4,967,927, issued Nov. 6, 1990 to Reiland et al.; U.S. Pat. No. 5,199,592, issued Apr. 6, 1993 to Reiland et al.; U.S. Pat. No. 5,474,197, issued Dec. 12, 1995 to Hillis et al.; U.S. Pat. No. 5,788,103, issued Aug. 4, 1998 to Wagner et al.; and U.S. patent application Ser. No. 08/567,385, filed Dec. 4, 1995, by Hillis et al. and identified by (each of the foregoing patent documents are incorporated herein by reference in their entirety for all purposes).
Collapsible containers are typically formed from injection-molded plastics, for example high-density polyethylene. A principal obstacle encountered with previous molded plastic containers for heavy industrial and agricultural purposes has been the difficulty in providing foldable walls which, when erected, are strong enough to carry heavy loads such as machine parts or heavy metal objects, as well as large volumes of farm produce, meat and other heavy food items. The use of such reinforcing devices as metal clips, hinge pins, struts, beams and other reinforcing members to add strength and durability to the container walls and hinge elements is undesirable. In particular, such metal parts may become separated and lost when the container is collapsed for return shipment. In addition, such designs involve the use of separate or compound parts made of diverse materials, which are prohibitively expensive to manufacture and would render the containers too cumbersome to be practical. Other considerations such as replacement of worn out parts and the ability to keep the container structure clean, further detract from the use of such reinforcing members.
In order to accommodate the heavy load requirements of industrial and agricultural, collapsible containers, the stiffness and strength of the base and side walls have typically been reinforced by adding support elements, such as support beams, struts and waffle plates, integrally molded in the base and side walls of the container. Examples of ribbing and beam patterns that have been used to reinforce bases and side walls of collapsible containers are provided in U.S. Pat. No. 4,674,647, issued Jun. 23, 1987 to Gyenge et al; U.S. Pat. No. 4,775,068, issued Oct. 4, 1988 to Reiland et al; and U.S. Pat. No. 5,114,037, issued May 19, 1992 to Hills et al. (each incorporated herein by reference).
Although these reinforcement techniques produce high strength collapsible containers with large load capacities, they have several disadvantages for containers used to transport and store foodstuffs and other goods that are vulnerable to mechanical damage and/or contamination. In this context, container designs that feature reinforcing beams, ribbing or waffle plates for shipping and storing agricultural products tend to become clogged with grime, dirt, or crushed produce. This raises substantial problems with respect to food sanitation. Likewise, ribbed or waffled support surfaces can impart harmful contaminants to other sensitive products, including fine machine parts and goods packaged for retail sale. To compound these deficiencies, ribbed and waffled support surfaces of previously known collapsible containers have numerous comers, angles, ridges and recesses that are difficult to reach with detergents and antiseptics and to flush clean after use.
More recent efforts to develop high strength collapsible containers for transport and storage of foodstuffs and other goods subject to damage and contamination have been directed toward providing smooth base and side wall surfaces. For example, U.S. Pat. No. 5,788,103, issued Aug. 4, 1998 to Wagner et al., describes a collapsible container with smooth base and side wall surfaces that reduce contamination and improve cleaning ability. However, the side walls incorporate vents and vertical strut elements that still provide undesirable niches for contaminants to accumulate and barriers that reduce penetration of cleansers and flushing liquids.
Accordingly, there is an unmet need in the art for a collapsible container having side walls which can support heavy loads of agricultural and industrial goods materials, but which minimizes the risk of contamination of these materials when transported or stored in the container.
In addition, there is a need in the art for a collapsible container for heavy agricultural and industrial use which can be thoroughly surface-exposed after use to detergents and decontaminating agents and flushed free of contaminants and cleansing agents for safe reuse.
It is therefore an object of the instant invention to provide a collapsible container having a new and improved construction that minimizes exposed structural elements and support surfaces for sanitary purposes, but which nonetheless provides sufficient structural support for heavy agricultural and industrial use.
It is a related object of the invention to provide such a container which incorporates side and end walls having a minimal exposed surface area and which eliminates unnecessary comers, angles, recesses and other niches where grime and pathogenic agents can be deposited and retained to impose unacceptable contamination risks to food and other sensitive articles placed in the container.
It is a further object of the invention to achieve the above objects in a collapsible container that provides for improved access to the contents of the container when access through the top is impractical, such as when the top is covered, when the containers are stacked, or when the container is at an elevation to make access through the top opening impractical. Toward this end, it is an object of the invention to provide a collapsible container having an opening in a container side wall that is closeable with a hinged gate, wherein the side wall and gate satisfy the above needs of providing sufficient strength and support while minimizing exposed support surfaces prone to contamination.
The instant invention satisfies the foregoing needs and fulfills additional objects and advantages that will become apparent from the description which follows in conjunction with the accompanying drawings.
In brief summary, the instant invention provides a novel, collapsible container which includes a container base joined to an upright opposing pair of side walls and opposing pair of end walls. Each of the side walls and end walls have a novel, closed, multi-paneled element forming at least a portion of the wall, which is formed from an exterior panel and an interior panel that are joined along top, side and bottom seams of the panel, preferably by hot plate welding, to form a closed, multi-paneled side or end wall element.
In more detailed aspects of the invention, the side or end walls incorporate a novel windowed construction, which includes a window with a seam surrounding a single panel window area.
In other detailed aspects of the invention, the collapsible container features at least one of the top, side and bottom seams of the side or end wall is a flashless seam.
In certain embodiments of the invention, the collapsible container of the invention incorporates a hinged access door having a closed, multi-paneled construction.
In additional embodiments, the collapsible container includes a multi-part forklift strap attached to the container base. The forklift strap preferably includes two interchangeable strap halves. The interchangeable strap halves feature interlocking dovetail connector ends having opposing faces that feature multiple, differently drafted surfaces.
In yet additional aspects of the invention, a collapsible container is provided which incorporates a novel, floating cantilever hinge design for interlocking the side and end walls to the base. Other hinge designs provided within the invention include hinges that incorporate self-bailing hinge pockets.
In related aspects of the invention, methods for producing a side or end wall for a collapsible container are provided which include steps of separately molding container side wall and end wall exterior and interior panels, and subsequently welding the panels along top, side and bottom seams to form a closed side wall structure.